mmc: host: Improve I/O read/write performance for GL9763E

Due to flaws in hardware design, GL9763E takes long time to exit from L1
state. The I/O performance will suffer severe impact if it often enter and
exit L1 state during I/O requests.

To improve I/O read/write performance and take battery life into account,
let's turn on GL9763E L1 negotiation before entering runtime suspend and
turn off GL9763E L1 negotiation while executing runtime resume. That is to
say, GL9763E will not enter L1 state when executing I/O requests and enter
L1 state when PCIe bus idle.

Signed-off-by: Renius Chen <reniuschengl@gmail.com>
Signed-off-by: Jason Lai <jason.lai@genesyslogic.com.tw>
Link: https://lore.kernel.org/r/20220613092907.2502-1-jason.lai@genesyslogic.com.tw


[Ulf: Improved the commit message a bit]
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>